Bluetooth Classic (BTC) and Bluetooth Low Energy (BTLE) are communication protocols that are commonly used to enable mobile computing devices to communicate with one another. BTC is a short-range wireless communications technology that operates in the 2.4 GHz industrial, scientific, and medical (ISM) band, utilizes a spread-spectrum frequency hopping scheme, and currently provides data throughput of around 2.5 Mbps. BTLE is a short-range wireless communications technology that also operates in the 2.4 GHz ISM band and provides reduced power consumption in comparison to BTC. The data throughput of BTLE, however, is substantially constrained in comparison to BTC, and is currently limited to around 100 Kbps.
Generally, a master device and a slave device exchange a number of packets to establish a Bluetooth Classic (BTC) connection or a Bluetooth Low Energy (BTLE) connection. The master device can also be referred to as a central device, while slave devices can also be referred to as peripheral devices. Typically, to set up a BTC connection, the master device continuously transmits page packets to a slave device over multiple frequencies. Each page packet includes a Device Access Code (DAC) of a slave device for which the page packet is intended. A particular slave device, in a page scan mode, scans for and isolates the page packets that include the DAC of the slave device. When the master device transmits a page packet at a particular time and frequency, and the slave device receives the page packet at the same time and frequency, then transmission by the master device and reception by the slave device of the page packet is coarsely aligned in time and in frequency hopping. In turn, the slave device transmits a page response to the master device to acknowledge receipt of the page packet. Thereafter, the master device and the slave device exchange additional packets to carry out clock synchronization and establish the BTC connection.
Notably, the BTC connection setup process can be power-intensive because the master device continuously transmits page packets to the slave device to attempt to discover the slave device. The slave device, when unpaired, remains in a page scan mode to be able to receive and acknowledge the page packets. The BTC connection setup is also time-intensive because the transmission and reception of the page packets between the master device and the slave device needs to be aligned prior to establishing the BTC connection. Typically, the BTC connection setup takes about 1-4 seconds to complete depending on a variety of factors, e.g., how quickly the devices align in time and frequency hopping to send and receive page packets and page response packets, whether the slave device is performing another task while performing the page scan or is connected to other devices over BTLE or BTC (which increases the time needed for alignment), and the like. The BTC connection setup is also bandwidth-intensive because the master device can spend a considerable amount of time using the bandwidth to transmit the page packets, which is especially significant as it impacts other high-priority bandwidth-intensive tasks (e.g., music playback) simultaneously being carried out that should not be interrupted.